I've got the Leica 1.25x and the Japan Exposures 1.15x.
For normal FL like 28 35 50, I prefer the JE 1.15x, but for longer FL the 1.25 or higher, if I owned one.
The JE has a built in diopter adjuster - 3.0 to +3.0 (I think, I'm only -1 so, I don't know how well the other settings work)
Only the Leica is rubberized on the rim of the eyepiece, which is useful if to prevent scratching your eye glasses, presumably you take off your eyeglasses on the JE since it has a built-in Diopter adjuster.